In Mice, A High-Fiber Diet Reduces Food Allergies

With the recent rise in reported food allergies, scientists have become increasingly interested in finding the cause of this major public health issue. A new animal study published in Cell Reports that has identified a link between diet, gut bacteria, and the development of food allergies, could shed some light on this issue.

In one part of the study, mice on a long-term high-fiber diet, which was designed to promote the growth of healthy intestinal bacteria, were less likely to have an allergic reaction when exposed to a peanut extract than mice on a zero-fiber diet. The high-fiber diet was found to alter the make-up of the bacteria living in the mice’s intestines and to increase the bacterial production of short-chain fatty acids, which are known to support the health of the large intestine’s lining. The high-fiber diet also shifted immune system activity, favoring immune cells that regulated inflammation. In other experiments described in this study, the researchers found that the anti-allergy effect of the high-fiber diet relied on both the proper use of short-chain fatty acids and the increased activity of regulatory immune cells, as well as adequate amounts of vitamin A. Furthermore, they showed that peanut tolerance (the opposite of a peanut allergy) could be induced by transplanting bacterial colonies from the high-fiber-fed mice into the zero-fiber-fed mice whose intestines had no bacteria of their own.

In short, the results of these experiments suggest that healthy gut bacteria are crucial for preventing food allergies and that a high-fiber diet is essential for growing and maintaining healthy gut bacteria. One of the study’s co-authors, Laurence Macia, said of the findings, “My theory is that the beneficial bacteria that predominate under [the] consumption of fiber promote the development of regulatory T cells, which ensures the bacteria have a healthy, anti-inflammatory system to thrive in.” Although these intriguing results may not apply to humans, the researchers expressed cautious optimism that their findings will someday prove to be useful in developing allergy prevention and treatment strategies.